The present invention concerns a pure steam generator comprising a feed line for conducting feed water into the pure steam generator, a heating steam input, heat exchange apparatus for accomplishing heat exchange between the heating steam and the feed water, a pure steam output, a separation space located in a lower part of the pure steam generator, and a centrifugal separator which is arranged so that the pure steam flows therethrough from the separation space to the pure steam output.
Exceedingly strict quality requirements are imposed on pure or sterile steam to be used in steam sterilization in the pharmaceutical industry. The pure or sterilizing steam must also be absolutely free from pyrogenic impurities. It should be noted that if the steam used for sterilizing is not absolutely free from pyrogens, then drug packaging treated with such steam may be damaged, with result that such drug packaging will be unfit for use.
The pure steam generator is, in fact, a distilling apparatus having no condenser, with the pure steam so generated in fact being the same as uncondensed distillate, used, for example, in injection solutions.
In pure steam generators, purity requirements have been solved in a design of the prior art, by providing feed water that is pyrogen-free. In this case, the steam which is produced is clearly free from pyrogens. However, using this kind of high-quality feed water involves considerable expense, and therefore this design of the prior art is not the best possible solution to the problem with respect to economies and conservation.
In view of this, it is general practice to use impure feed water in pure steam generators known in the art. The feed water is conducted with the aid of a feed pump along a feed line, generally through a waste water heat exchanger and a condensate heat exchanger for the condensate of the heating steam, and then through a feed water input connector to a distribution space in the upper part of the pure steam generator, where the feed water flows in heat exchange with a heat exchange tubing system downwardly; from the lower part of the pure steam generator, the pure steam so generated is conducted through a centrifugal separator to the pure steam output. The condensate of the heating steam is conducted to the heating steam condensate heat exchanger, while the waste water from the feed water passing through the heat exchange tubing system, is conducted to the waste water heat exchanger, to pre-heat the feed water.
A drawback of the pure steam generator of the prior art described above, is that when pure steam is not drawn from the pure steam generator for consumption, there is a risk that when pure steam is again drawn for consumption, the first few liters thereof will contain impurities, in particular pyrogenic impurities.